The present invention relates to a heat exchanger with a thermal storage function and to a method of manufacturing the same.
In order to protect the environment and improve fuel consumption of automobiles, there has been proposed an automobile designed to automatically stop the engine when the automobile stops, for example, to wait for a traffic light to change.
However, an ordinary car air conditioner has a problem in that, when an engine of an automobile in which the air conditioner is mounted is stopped, a compressor driven by the engine is stopped, and supply of refrigerant (medium to transport the cool) to an evaporator stops, whereby the cooling capacity of the air conditioner drops sharply.
As one measure to solve such a problem, imparting a cool storage function to the evaporator has been considered, to thereby enable cooling of a vehicle compartment by releasing the cool stored in the evaporator, when the compressor stops as a result of stoppage of the engine.
In a proposed evaporator with a cool storage function (see Japanese Patent Application Laid-Open (kokai) No. 2011-12947), a plurality of flat refrigerant flow tubes (heat exchanger tubes) which extend in the vertical direction and whose width direction coincides with an air-passing direction are disposed in parallel at intervals to thereby form clearances between the adjacent refrigerant flow tubes. Some of the clearances accommodate respective cool storage material containers in which a thermal storage medium for storing the cool; i.e., a cool storage material, is contained. The remaining clearances accommodate respective outer fins. Each of the cool storage medium containers is formed by joining two metal plates at their peripheral portions. The cool storage medium is contained in a cool storage medium containing space provided between the two metal plates.
Although not specified in the above publication, in order to contain the cool storage material in the cool storage material container, the cool storage material container must have a cool storage material charging inlet in the form of a cylindrical hole. After the cool storage material is charged into the cool storage material containing space through the cool storage material charging inlet, the cool storage material charging inlet must be closed.
Meanwhile, in the evaporator with a cool storage function described in the above publication, the cool storage material charging inlet in the form of a cylindrical hole is considered to be easily formed on the cool storage material container as follows. An outwardly protruding semicylindrical portion is provided at a peripheral portion of each of the metal plates. Outward flanges are provided at respective opposite side edges of each of the semicylindrical portions. In joining the metal plates, the corresponding outward flanges are joined together, thereby forming the cool storage material charging inlet. Also, the cool storage material charging inlet is considered to be easily closed by, after charge of the cool storage material, press-fitting a circular columnar plug into the cool storage material charging inlet.
Usually, in manufacture of the two metal plates used to form the above cool storage material container, two metal blank plates are subjected to pressing by use of two dies having shapes corresponding to the final shapes of the two metal plates, respectively. In this case, a clearance is unavoidably formed between the plug and the inner circumferential surface of the cylindrical hole formed by the semicylindrical portions of the two metal plates.